The evolution of the pneumatic tire has since its early days been affected by a desire on the part of consumers, particularly in the United States, to impart an extent of color or adornment to the characteristic black coloration of pneumatic tires. As a result, the incorporation of whitewalls in a portion of the sidewalls of pneumatic tires particularly for automobiles dates back many years. More recently whitewalls have appeared in variations involving the use of a plurality of stripes, stripes in colors other than white, stripes in varying widths, and combinations of these variables. An even more recent variation of whitewall decoration for the sidewalls of pneumatic tires has taken the form of raised white or colored letters which identify the manufacturer, a designation for a particular tire configuration, or other indicia.
In all instances such color decoration for pneumatic tires has generally been effected in one of two ways. In one technique, whitewall materials are incorporated by extruding the desired colored compound simultaneously with the sidewall stock of the tire during the initial fabrication of components or building stage. In the other technique, the whitewall element is applied subsequent to the final shaping and curing of the tire.
Most common is the first technique which contemplates embedding the desired colored compound into the characteristic black sidewall stock of the tire during the extruding or the fabrication of the sidewall and prior to the first stages of tire fabrication or building. The colored compound is normally covered with a thin layer or laminate of black sidewall stock commonly referred to as a cover strip. The tire is subsequently completed in conventional fashion as in the manufacture of a standard black wall tire through the shaping and vulcanization steps. Subsequent to vulcanization, grinding or buffing equipment is employed to remove such portions of the cover strip as is required to expose the extent of colored compound necessary to achieve the predetermined desired decorative effect.While whitewall tires so constructed have enjoyed substantial commercial success, their acceptance has been somewhat restricted due to the substantial additional cost brought about by the necessity for additional processing steps. These additional processing steps also commensurately increase the probability of an imperfection in the splice area, the joinder of the colored compound to the conventional black sidewall stock or the colored area exposed such that a rejected or at least a blemished tire may result. Despite improvements in materials and processing techniques, these problems persist to an extent to the present time.
The other technique wherein the whitewall element is applied subsequent to the final shaping and curing of the tire is accomplished by generally two approaches. One approach contemplates the attachment of a colored element to the sidewall of the tire as by either bonding techniques or mechanical attachment to flaps or overhanging shoulders formed in the sidewall of a tire. In the other approach, the whitewall element is attached to the tire rim, wheel or wheel cover elements in such a manner as to overlie a portion of the sidewall of the tire to be decorated. Sidewall decorations attached according to this approach have generally not been widely accepted due to difficulty in establishing a configuration which remains permanently attached to and will not separate from the tire despite the flexural characteristics of the tire and the abuse to which tires are intermittently subjected in conjunction with normal usage.
To applicant's knowledge whitewalls produced by either of the above-discussed techniques have not been designed in such a fashion as to constitute a structural element in the tire carcass configuration. Rather, the whitewalls have been constructed in such fashion as to produce the required attachment compatibility with the tire sidewall components and to be of a material having characteristics of durability commensurate with the contemplated life of the tire.
It is, however, otherwise known to provide reinforcing components in the sidewall portions of pneumatic tires. Since conventional bias ply tire carcasses exhibit generally uniform characteristics throughout the sidewall area, reinforcement is generally not necessary to provide characteristics compatible with the operating parameters normally sought for pneumatic tires. In regard to radial ply tires, the radial compressibility and extensibility of the sidewall cord members of the carcass produce an extent of flexibility which is considered desirable in effecting comfortable ride characteristics. In order to provide the desired substantial rigidity in the tread area for reduced rolling resistance, it is in many instances desirable to increase the rigidity of the sidewalls above and below the flex point by reinforcement without sacrificing the radial compressibility and extensibility thereof; however, in most such instances a weak spot is built into the flex area, particularly where the splice of the sidewall is made during the fabrication process.
It is also known to provide reinforcement to limited areas but not all of the sidewall region so as to achieve an extent of reinforcement of the sidewall while preserving to a maximum extent the radial extensibility and compressibility characteristics. Thus, reinforcing wires, rubber cords, rods and like structural elements have been incorporated in radial tires at, for example, areas of substantial change in curvature and angled elastic cords have been incorporated over a portion of the radial extent of the carcass of radial pneumatic tires. To applicant's knowledge these sidewall reinforcing members are normally incorporated into the cord configuration of the tire carcass by overlapping, intertwining or comparable construction techniques involved in the initial fabrication or building of the tire carcass. These sidewall reinforcement elements are thus not positioned exteriorly of a tire sidewall portion such that they have constituted or could potentially constitute a decorative element of the tire.